The invention relates generally to an isolation mounting system for data storage modules and, more particularly, to a mounting system that includes a lock to hold the module firmly in place in its final/operational position.
Redundant arrays of inexpensive or independent data storage devices (RAID) are being employed by the mass storage industry to provide variable capacity data storage. RAID systems use interconnected disk drives to achieve the desired capacity of mass storage. With this approach, a disk drive of one capacity may be manufactured and packaged with the same or different capacity drives to provide the required storage capacity. RAID systems eliminate the need to manufacture disk drives individually designed to meet specific storage requirements. Each disk drive in a RAID system is usually housed in an individual module. The modules are handled manually for shipping, installation and the like. The modules slide into and out of an enclosure or rack that houses the array of disk drives and provides the sockets, plug-ins and other connections for the electrical interconnection of the drives. Controllers orchestrate the interconnection and control access to selected disk drives for data reading and writing operations.
Disk drives are high precision electro-mechanical devices in which the read/write transducer heads fly on an air bearing at the surface of the disks. The flight height of the head is only a few micro-inches from the disk surface. This and other sensitive aspects of the disk drives make them vulnerable to damage during shipping and handling. Consequently, some type of shock mounting system is often used to isolate the disk drive from the module. Typically, compliant members such as elastomeric disks or doughnuts are interposed between the disk drive and the module housing to isolate the disk drive from its housing. One such isolation system is described in U.S. Pat. No. 5,668,697 titled Data Storage Module Having Cradles On Housing And Elastomeric Member Mounted On Data Storage Mechanism. The compliant members attenuate external shock and vibration inputs to the disk drive. During operation of the disk drive, however, the compliant members can introduce self-excited rotational modes of the disk drive mechanism. That is, the same cushioning characteristics of the compliant members that attenuate external shock and vibration introduce a degree of freedom of movement that allows the disk drive to react to its own actuator movement. Self-excitement can be a significant problem when torque is applied to the actuator during seeking operations. The actuator torque creates a reaction torque that tends to rotate the disk drive in a direction opposite the direction of the actuator torque. Rotating the disk drive can cause off track errors of the actuator, particularly with increasing track densities, which leads to errors reading data from the disks and writing data to the disks.
Accordingly, the present invention is directed to an isolation mounting system for disk drive and other storage modules in which the operating unit (e.g., a disk drive) is locked more firmly into its operating position. During shipping and installation the lock is disengaged to allow full use of the elastomeric or other shock mounting system. Thus, the present invention simulates a stiff mount system during operation and a soft mount system during shipping and handling. A data storage module constructed according to one embodiment of the invention includes a data storage device, typically a disk drive, shock mounted in a housing and a lock selectively engagable between the data storage device and the housing. The lock is operable between a first disengaged position in which the lock does not restrict movement of the data storage device within the housing and a second engaged position in which the lock restricts substantially all movement of the data storage device within the housing. In one preferred version of this embodiment, the lock consists of wedges inserted at each shock mount to effectively remove the bulk of the characteristic compliance. This wedge locking system, which will tend to raise the resonant frequencies in all modes, should reduce the amount of self-excitement in the rotational mode during actuator seeking.
In a second embodiment of the invention, the data storage module includes lock blocks connected to the data storage device. The lock blocks are movable between a first disengaged position in which the blocks do not restrict movement of the data storage device within the housing and a second engaged position in which each block extends through an opening in the side of the housing to restrict substantially all movement of the data storage device within the housing. In one preferred version of this embodiment, a camming device connecting the lock blocks and the data storage device is used to move the blocks from the unlocked position to the locked position, or from the locked position to the second position.
Unless expressly and clearly stated otherwise, xe2x80x9caxe2x80x9d something in this Specification and in the Claims means one or more of that something. For example, xe2x80x9ca lockxe2x80x9d in claim 1 means one or more locks and xe2x80x9ca wedgexe2x80x9d in claim 2 means one or more wedges.